Process of producing dull-luster bactericidal filament



laeliki 5R KR 29Q72s85 Patented Mar. 2, 1937 UNIT 7% 5/51; 5 i

Rudolph S. Bley, Elizabethton, Tenn., assignor to North American Rayon Corporation, New York, N; Y., a corporation of Delaware No Drawing. Application October 11, 1934, Serial No. 747,895

10 Claims.

The present invention relates to a process of producing dull-luster cellulosic filaments having bactericidal properties.

One object of my invention is the dispersion 5 of an organosol, containing at least two dissimilar, colloidal metals into cellulosic spinning solutions to form subsequently by extrusion into conventional setting baths or air delustered, bactericidal filaments.

10 Another object of my invention relates to a pre-irradiation of the organosols and colloidal metals with ultra-violet rays.

' A third object of the presentinvention has to do with a novel product per se, namely dull-luster, 15 bactericidal filament of cellulosic origin.

Other objects of my invention will become ap-' parent to those skilled in the art from a study of the following specification.

I am .well aware that it has, heretofore, been proposed to use colloidal metals as disinfectants (vide ,Rideal, Disinfection and Sterilizationl, 1921, .pages 206-9), and to impregnate textile fibers with metallic salts and colloidal hydroxides (vide U. S. Patents Nos. 22,362, 1,482,416, 1,536,254 and 1,717,483) :toprevent fungous growth. I am Q also aware that ithas, heretofore, been proposed to add hydrocarbons, vegetable and mineral oils, pigments, etc.;to "cellulosic spinning solutions to produce. dull-luster filaments, but-I believe myself to. be the first inventor to produce dull-luster, bactericidal products of cellulosic origin. I

- I have found by experimentation that colloidal metals per se have a relatively weak sterilizing effect, especially when being imbedded in cellu- 35 losic filaments. After a thorough investigation of the effect of colloidal metals as well as colloidal metal compounds upon non-pathogenic microorganisms such as bacteria and molds, I have found that the bactericidal effect of the afore- 4 mentioned substances can be substantially increased and accelerated by distributing two or more dissimilar, colloidal metals into cellulosic spinning solutions.

In order to increase and/or accelerate the bac- 4 tericidal properties of colloidal metals, it is necessary to select at least two dissimilar metals.

When microorganisms, such as bacteria, molds,

etc., are distributed in a liquid phase and subsequently a solid phase, such-as colloidal metal, 50 is added thereto, they are killed after a while and the liquid becomes sterile. The time consumed to paralyze the protoplasma of microorganisms naturally depends upon the species of microorganisms treated, the chemical composition and v 55 temperature of the nutritive solution and the amounts and chemical properties of the colloidal metals used as disinfectants. The physico-chemical principles underlying this sterilization are unknown, although the theory has been advanced 60 that the colloidal metal particles become ad- NO $4 s... at

sorbed to the membranes of the microorganisms and in turn prevent proper assimilation ofnutritive substances. Other investigators have claimed visible ms 2 da been unable to definitely find t e cause why cells of microorganisms are much more rapidly killed in the presence of two or more dissimilar, colloidal metals.

Table 1 depicts the results obtained by using 10 various colloidal substances, in accordance with the present invention, to sterilize aqueous suspensions of Bacillus coli, an organism commonly appearing in fouling liquids. To obtain comparable results, aqueous suspensions of Bacillus coli .were prepared by inoculation into sterile water.

Subsequently, equal amounts of this bacterial suspension were transferred by means of a platinurn loop. into test tubes containing identical quantities of sterile beef broth gelatine. After thoroughly shaking each inoculated test tube to evenly distribute the bacterial cells in the nutritive, molten gelatine an equal amount of disinfectant was added to the test tubes and the same incubated, after thorough shaking, at a tempera- 'ture of about 37.5" C. To determine the exact period of time necessary to sterilize the cultures, each tube was opened at five minute intervals under sterile conditions and a loop of the cultures inoculated into new sterile beef-broth gelatine:

tubes. The first tube of each series, showing no I growth on incubation for several days, was considered the characteristic one for each disinfectaut tested.

Table I Bacillus coli cultivated in beef brothgelatine at 37.5 C.

One loop of bacterial suspension inoculated into every test tube can teiniug 10 cc. of gelatine. 0.1 g. of disinfectant in 1 cc. of distilled water and 0.01 g. gelatine as protective colloid.

x indicates that Bacillus coli is growing.

- indicates that Bacillus coli is dead.

When using composite disinfectants, equal amounts of each ingredient were used to make up 0.1 g. of disinfectant, for example 0.05 g. copper plus 0.05 g. silver, etc., although the ratio of the ingredients may be varied at will.

I have, furthermore, found that colloidal metals, irradiated with ultra-violet rays, prior to being used as disinfectants, have a greater bactericidal power than non-irradiated ones. Although ultra-violet rays stimulate the aforementioned colloidal disinfectants to a higher degree than daylight, it is to be noted that a prolonged irradiation fails to increase the bactericidal effect of a disinfectant beyond a fixed limit. This limit varies for each metal, and combinations thereof, and it must be determined by experiment, in other words, each colloidal agent has a definite optimum time of irradiation. Over-exposure to ultra-violet rays does not deleteriously affect the colloidal disinfectants, but it should be avoided for reasons of economy. I am unable to define the complex reactions which evidently take place in such irradiated dispersons, but I have definitely found that the agents, cited above, substantially increase their bactericidal powers after being irradiated. This stimulation by means of irradiation is so pronounced that even the walls of glass flasks in which they are kept acquire bactericidal properties. When, for example, all colloidal metals are removed from such a flask by rinsing and the same is filled with a suspension of virulent bacteria, the bacteria will be killed after standing for some time. This experiment can be repeated several times, the glass walls acting as disinfectants in the absence of colloidal particles; at least 7. have been unable to detect with the microscope any particles adsorbed to the glass walls of such flasks. Although I am unable to explain this phenomenon, a marked increase of the bactericidal power of my agents is obtained by pre-irradiation. Table II depicts some results obtained by this method.

Table II Effect of irradiation All dispersions were irradiated with ultra-violet rays in open glass dishes prior to being used as disinfectants. After inoculation,

the tubes were kept in a dark incubator. (See Table 1.)

Similar results were obtained with spores of Mucor'and Oidium species, although they are more resistant to destruction. After standing in the darkfor 14 days, the irradiated colloidal disinfectants were again compared with the non- 60 irradiated ones. The pre-irradiated disinfectants had retained greater sterilizing powers than the non-irradiated ones. It is to be noted, however, that the sterilization, obtained by pre-irradiation, slowly abates on standing, and that it may be revived by a second irradiation, etc.

The colloidal dispersions may be prepared by wellknown processes to form suitable disinfectants. The metals and alloys may be dispersed by electrical means and held in aqueous suspension by adding thereto suitable protective colloids, such as gelatine, agar, gums, alginates, casein, soluble silicates, protalbic acid, etc., before being suspended in oils. Colloidal metals may also be formed by chemical precipitation in aqueous solutions. Subsequently, the by-products may be removed by dialysis, the dispersions dried at low temperatures and suspended in oils with or without protective colloids, to form metal organosols. Two or more colloidal metals may be simultaneously precipitated in the aforementioned manner. dialyzed, dried and suspended in oils. Collodial copper, for example, may be prepared in the following manner. A 20% aqueous solution of copper sulphate, containing about 10 to 20% saccharose, is boiled for a few minutes and subsequently diluted with an equal amount of distilled water, this comprising solution No. 1. Solution No. 2 consists of a 14% aqueous solution of sodium or potassium hydroxide. Solution No. 3 is prepared by adjusting sulphuric acid so that 1 cc. thereof corresponds to 2 cos. of the hydroxide solution. Solution No. 4 is obtained by dissolving approximately 5 g. of gelatine in 100 cos. of distilled water. After having prepared solutions 1 to 4, 10 ccs. of solution No. 1 are mixed with 40 ccs. of solution No. 4 and the mixture boiled on a water bath for a few minutes. About 5 to 6 ccs. of solution No. 2 are added to the hot mixture to precipitate colloidal cuprous hydroxide. This cuprous oxide is purified by dialysis, dried and suspended in suitable organic compounds to form a cuprous hydroxide organosol to which other colloidal metals may be added. To form colloidal copper from cuprous hydroxide, the solution is again boiled and subsequently 3 cos. of solution No. 3 added thereto. Red colloidal copper is spontaneously precipitated. This colloidal copper may be treated, as set forth above, to produce a copper organosol. Instead of using sulphuric acid to form colloidal copper, any acid may be employed in which colloidal copper is insoluble. Such colloidal metals and colloidal metal alloys may be also prepared by reducing water-soluble metal salts with aldehydes, p-aminophenol, etc. 1 g. of gold chloride for example, is dissolved in a few cos. of distilled water and added to 500 cos. of a 10% aqueous solution of vinyl alcohol. After addition of a mixture of 40 cos. of formaldehyde and 40 cos. of n-sodium carbonate solution, colloidal gold is precipitated which may be purified by dialysis. The purified colloids are dispersed in oils, hydrocarbons, etc., by means of ball or colloid mills.

organosols of metals may also be prepared in the following manner. 10 g. of silver nitrate, for example, are mixed with about 100 g. of a sterol, such as cholesterol, phytosterol, etc., and the mixture carefully heated to about 250 C. until a silver mirror appears on the surface of the composition. The heat-reaction products of sterols containing colloidal silver may. be suspended in oils, such as olive oil, Turkey red oil, mineral oils, animal oils, etc. Suitable protective colloids, such as oil soluble soaps, naphthenates, etc., may be added to stabilize the organosols. When such metal organosols are incorporated into cellulosic spinning solutions, bactericidal filaments are obtained which are simultaneously delustered.

Example I Two or more dissimilar, colloidal metals, for example, colloidal copper and zinc are dispersed in a vegetable, mineral or animal oil, to form an organosol which is emulsified with a conventional viscose spinning solution. The amounts of colloidal metals in an organosol, i. e., the solid phase of the organosol, may be varied at will. The amounts of oils, hydrocarbons, etc., to be added to the spinning solution, constituting the liquid phase of the organosol, may also be varied at will.

Thus, it is possible to produce more or less delustered, as well as more or less bactericidal fila-' ments and/or yarns. In order to prevent an externally visible change in color of the finished products, the organosol is adjusted so that about 0.25 to 1.0 g. of solid phase is incorporated into about 1000 got a viscous solution. In this manner.

it is possible to produce viscose products having I the same bactericidal power and yet a diflerent degree of luster. By varying the amount of solid phase in a given amount of liquid phase, it is possible to produce viscose products having an identical degree of luster and yet diiferent bactericidal properties. According to the amounts of liquid and solid phases present in the finished products, they may even have the appearance of dull metals. Instead of using copper, zinc, ilver,

\gli-d any combinati o a is uitable which is able to set up a sufiicient potential difference in the presence of electrolytes, such as the minute salt residues present in finished cellulosic products. As soon as the finished product becomes exposed to moist air, etc., the potential difference, caused by the dissimilar metals,

will be suflicient to prevent growth of microorganisms therein and thereon. Pre-irradiated metal dispersions may replace non-irradiated colloidal metals to increase the bactericidal properties of the finished product. Instead of using viscose solutions in combination with my disinfectants, it is possible to incorporate the same into any known type of cellulosic spinning solutions, such se, cellulose esters, cellulose e ers, etc. Care has to be taken, however, in selecting proper colloidal metals. Should a metal be incorporated which is decomposed by the spinning solution, the resulting gas will cause the formation of hollow filaments. Should such hollow filaments be desired, it is necessary to incor- 40 porate at least one easily decomposed metal together with other stable colloidal metals into the spinning solution prior to the extrusion thereof. It is also necessary that the colloidal metals are unaflfected by the liquidphase of the organosol, 4 and that this liquid phase is immiscible with the spinning solutions. To produce dull-luster filaments, the liquid phase should have a diiferent index of refraction than the spinning solution with which it is to be emulsified. Thus, an almost unlimited number of organic liquids may be used as the liquid phases of my organosols, for example, vegetable oils, mineral oils, animal oils, hydrocarbons, essential oils, etc.

I wish to point out that the above example is merely illustrative, and I do not wish to be limited to the exact proportions set forth above, which are typical combinations, since certain of these ingredients may be omitted or replaced by others of similar nature, and the proportions within wide limits may be varied. In other words, while I have found that the colloidal metals above mentioned, give the desired results, I do not wish to be limited to the use of all of these substances and no others, nor the exact proportions and concen- G5 trations set forth above, as the omission of some ingredients or a slight variation of proportions will not adversely affect the final products, although it may vary somewhat the relative char acteristics of such products, resulting from such variations. I wish to emphasize that the term dissimilar metals, employed in the appended claims, embraces a combination of two or more chemically different metals or alloys which set up a more or less large potential diiference in the presence of minute amounts of electrolytes. These colloidal metals and alloys are called the solid phase of the organosol, while the oils, hydrocarbons, in which they are dispersed are termed the liquid phase of the organosol. Thus the organosol consists of solid and liquid phases which must be substantially insoluble in and inert to the spinning solutions as well as the treatmentbaths into which these solutions are extruded and otherwise treated. Modifications may be made in details of the method and product without departing from the spirit and scope of my invention, as defined by the appended claims.

I claim:

1. A cellulosic spinning solution for the manufacture of dull-luster, bactericidal cellulosic products comprising a cellulosic solution having an organosol emulsified therewith, said organosol including a plurality of colloidal, dissimilar metals dispersed in an organic liquid, said liquid being substantially immiscible with and inert to said cellulosic solution, and said metals being able to set up a potential difference in the presence of a minute amount of an electroLvte while bein stable in said organic liquid and said cellulosic solution.

2. A cellulosic spinning solution for the manufacture of dull-luster, bactericidal cellulosic products comprising a cellulosic solution having an organosol emulsified therewith, said organosol including a plurality of colloidal, dissimilar metals dispersed in a liquid hydrocarbon, said hydrocarbon being substantially immiscible with and inert to said cellulosic solution, and said metals being able to set up a potential difference in the presence of a minute amount of an electrolyte while being stable in said organic liquid and said cellu-' losic solution.

3. A cellulosic spinning solution for the manufacture of dull-luster, bactericidal cellulosic products comprising a cellulosic solution having an organosol emulsified therewith, said organosol including a plurality of colloidal, dissimilar metals dispersed in an organic liquid and able to set up a potential difierence in the presence of a minute amount of an electrolyte, said liquid being substantially immiscible with and inert to said cellulosic solution and said metals and said metals being pre-irradiated with ultra-violet rays.

4. A cellulosic spinning solution for the manufacture of dull-luster, bactericidal cellulosic products comprising a cellulosic solution having an organosol emulsified therewith, said organosol including a plurality of colloidal, dissimilar metals dispersed in a liquid hydrocarbon and able to set up a potential difference in the presence of a minute amount of an electrolyte, said hydrocarbon being substantially immiscible with and inert to said cellulosic solution and said metals and said metals being pre-irradiated with ultra-violet rays.

5. A cellulosic spinning solution for the manufacture of dull-luster, bactericidal cellulosic products comprising a viscose solution having an organosol emulsified therewith, said organosol including a plurality of colloidal, dissimilar metals dispersed in an organic liquid and able to set up a potential difference in the presence of an electrolyte, said liquid being substantially immiscible with and inert to said viscose solution and said metals.

6. A cellulosic spinning solution for the manufacture of dull-luster, bactericidal cellulosic products comprising a viscose solution having an organosol emulsified therewith, said o ganosol including a plurality of colloidal metals dispersed in a hydrocarbon and able to set up a potential difi'erence in the presence of a minute amount of an electrolyte, said hydrocarbon being substantially immiscible with and inert to said viscose solution and said metals.

'7. A cellulosic spinning solution for the manufacture of dull-luster, bactericidal cellulosic products comprising a viscose solution having an organosol emulsified therewith, said organosol including a plurality of colloidal dissimilar metals dispersed in an organic liquid and able to set up a potential difference in the presence of a minute amount of an electrolyte, said liquid being substantially immiscible with and inert to said viscose solution and said metals and said metals being pre-irradiated with ultra-violet rays.

8. A cellulosic spinning solution for the manufacture of dull-luster, bactericidal oeilulosic products comprising a viscose solution having an organosol emulsified therewith, said organosol including a plurality of colloidal, dissimilar metals dispersed in a hydrocarbon and able to set up a potential difference in the presence of a minute amount of an electrolyte, said hydrocarbon being substantially immiscible with and inert to said viscose solution and said metals and said metals being pre-irradiated with ultra-violet rays.

9. A dull-luster, bactericidal cellulosic product containing an organosol comprising a plurality of colloidal, dissimilar metals dispersed in an organic liquid inert with respect to said metals, said liquid forming globules in the product, and said metals being able to set up a potential difference in the presence of a minute amount of an electroly e.

10. A dull-luster, bactericidal cellulosic product containing an organosol comprising a plurality of colloidal, dissimilar metals dispersed in a hydrocarbon inert with respect to said metals, said hydrocarbon forming globules in the product, and said metals being able to set up a potential difference in the presence of a minute amount of an electrolyte.

RUDOLPH S. BLEY. 

